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AMCOM IV 2840R-02 Four-Diver Rack Mount Communicator with DSP3 Helium Speech Unscrambler

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  • High Audio Fidelity

    Ultra-low noise circuit combined with noise suppression circuitry produces crystal clear speech. Automatic gain adjustment will guard audio signal from distortion, enhance speaker protection and audio quality. Increases band width 47%.

  • Extended Battery Operation Time

    Audio amplifier card deploys the state-of-the-art Class-D digital audio power amplifier. Has very low power dissipation, produces less heat, and extends battery life up to 32%.

  • Flexible Gain Settings

    Audio amplifier card has adjustable gain settings to accommodate different communication applications and environments.

  • Ultra-Low Electromagnetic Interference (EMI)

    EMI is achieved through spread-spectrum and de-phase control techniques providing for optimum integration with diving systems.

  • Audio In/Out Connections

    Audio IN and audio OUT RCA connections supplied for receiving and sending standard audio line-level signals to and from another device. Two rack mount communicators can be interconnected for double redundancy requirements and/or can double the number of users as needed.


  • Helium Speech Unscrambler (HSU) incorporates a state-of-the-art digital signal processor to correct raw helium speech to clear, intelligible voice. The Depth Control can be finely-tuned using a multi-turn potentiometer providing the tender with better speech quality.
  • The Noise Reduction Filter (NRF) uses a complex Digital Signal Processor algorithm to capture the background noise and reduce it without affecting the diver’s speech. Noise reduction levels can be reduced by up to 17 dB.
  • Real-time audio processing uses both frequency and time domain technologies for optimized performance over a wide range of depths and background noise.
  • Improved Treble Boost Control feature allows for optimum frequency enhancement and improved intelligible speech from the diver’s voice.
  • Separate channels and volume controls for each diver and tender to accommodate individual earphone and microphone adjustments, equipment variations and individual comfort levels.
  • Divers’ umbilicals can be set up on 4-wire mode (full duplex) or 2-wire mode (push-to-talk) or any combination of the two modes for each diver.
  • Communicator comes standard with rear mounted MS connector, providing connections to diver and tender inputs and outputs.
  • Ability to use both dynamic and pre-amplified diver microphones with a unique circuit that detects microphone type and automatically adjusts volume levels.
  • Weatherproof push-to-talk microphone for better voice intelligibility topside.  For optimum clarity, see Tech Note (below) for other recommended equipment.
  • Battery Condition Indicator – Visual LED indicator of battery condition.
  • Internal charging system with battery back-up allows for simultaneous charging and operation of the unit while protecting the rechargeable battery from being overcharged.  Back-up battery automatically supplies power to the audio amplifier when AC power is disconnected to allow for continued operation up to 23 hours.


  • Input Impedance(Each Input): 250 Ohms
  • Frequency Response: 300 to 10,000Hz
  • Common Mode Rejection: 40 dB Minimum
  • Current Drain Maximum Full Volume: 3 Amps
  • Minimum Quiescent: 0.190 Amps
  • Output Impedance: 4 Ohm
  • Power Supply Voltage: 12 VDC Nominal (9 Volts Minimum – 18 Volts Maximum)
  • AC Voltage Range: 90-264 VAC, 50-60 Hz
  • Sensitivity (input): 0.5 mV
  • Output Power (RMS @ 4 Ohm Load, 12 VDC) : 10 Watts Audio
  • Rear Connector Input/Output: 20 Pin Female MS
  • Enclosure: 19 in. Rack, Aluminum, Black Anodized
  • Back-Up Battery: 1 ea. 12 VDC Rechargeable Battery
  • Dimensions: 7 in. H x 19 in. W x 12.5 in. D (17.8 cm x 48.25 cm x 31.75 cm)
  • Weight: 19.5 lbs. (8.8 kg)


AMCOM IV 2840R-02 Four-Diver Rack Mount Communicator with DSP3 Helium Speech Unscrambler includes:

  • (1) Amron 2405-28 Hand-Held Push-to-Talk Microphone
  • (1) Amron 2890-05 12 VDC Rechargeable Sealed Lead Acid Gel-Cell Battery
  • (1) MS-3106A-28-12P – MS Connector – 26 Pin for Four-Diver Communicators
  • (1) MS-3057-16A Cable Clamp – Green
  • (1) Amron P-2392 Power Cord
  • (1) Amron 284XR-UM Four-Diver Rack Mount Communicator User Manual


  • Amron 2401-28 Deluxe Headset with Boom Mic
  • Amron 2460-28 Standard Headset with Boom Mic
  • Amron 2822-28 Remote Walk-and-Talk (4-wire mode)
  • Amron 2821-28 Remote Walk-and-Talk (2-wire mode)


All communicators will inherently transfer topside noise to the divers when the tender speaks directly into the communicator’s panel speaker. To eliminate background noise at the surface, use the 2405-28 Push-to-Talk Microphone, included with this model.  For optimum communications, we recommend purchasing the 2401-28 Deluxe Headset with Boom Mic. For tender maneuverability, use the 2401-28 Deluxe Headset with Boom Mic along with the 2822-28 Remote Walk-and-Talk (4-wire mode) or the 2821-28 Remote Walk-and-Talk (2-wire mode). For standard air communications, order the 2840R-01 Four-Diver Rack Mount Communicator.

SKU: 2840R-02

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